This application claims the priority of German Patent Document DE 100 24 879.9, filed in Germany, May 19, 2000, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a seat module, which is intended for a vehicle seat, is designed as a seat cushion or backrest and can be actively ventilated. Preferred embodiments of the invention relate to a seat module comprising a cushion, which has a lower foam cushion layer impermeable to air, a central air-guiding layer made from a knitted spacing fabric and an air-permeable upper foam cushion layer and is covered with a cushion cover and divided by tacking that fixes the cushion cover into a face area and two side areas, which extend in the longitudinal direction and adjoin the latter, and having a cushion carrier that accommodates the cushion.
In the case of a known seat module of this kind (DE 196 28 698 C1, corresponding U.S. Pat. No. 5,902,014), which is designed as a seat cushion, the seat module is ventilated by arranging in the lower foam cushion layer resting on the cushion carrier, referred to as the cushion pad, a multiplicity of channels that penetrate the cushion pad vertically and in each of which a miniature fan is inserted. Each of the miniature fans is assigned to one area of the cushion separated off by tacking. The fans draw in air from the area of the vehicle""s interior below the seat module and blow it into the air-guiding layer. In the knitted spacing fabric of the air-guiding layer, the air can spread out in all directions and, if the seat module is unoccupied, can flow out through the upper foam cushion layer and the cushion cover into the air space above the surface of the module and thereby effect rapid cooling of the surface of the module. If the seat module is occupied, the air flows along the air-guiding layer of the knitted spacing fabric and re-emerges at the open ends of the cushion. In the process, it produces an air-humidity gradient and carries away the air humidified by the seated person.
To reduce costs in the case of a likewise known seat module with active seat ventilation (DE 198 04 284 A1, corresponding U.S. Pat. No. 6,019.420), the air-guiding layer is composed of rubberized hair and rests as a cushion pad on the cushion carrier. An air-impermeable film or an air-impermeable foam layer is inserted between the cushion pad and the cushion carrier. The foam layer has at least one air inflow opening, at which a miniature fan is arranged below the foam layer. The air-guiding layer is covered by a cushion cover with a cover filling of wadding, non-woven wool or the like in between, into which it is also possible to insert a seat heating system.
In the case of a known seat module designed as a backrest (DE 197 45 521 A1, corresponding U.S. Pat. No. 6,206,465), the cushion is secured on a cushion carrier clamped in the frame of the backrest. The cushion is embodied with a face area and two bolster-type side areas. The face area and the side areas are formed in the cushion by means of so-called tacking channels. The cushion comprises a foam cushion pad that rests on the cushion carrier, an air-guiding layer comprising a coarse-mesh knitted spacing fabric that covers the entire surface of the cushion pad in the face area, an air-permeable pressure distribution layer composed of an open-cell foam resting on the air-guiding layer, and an air-permeable cushion cover that covers the surface of the cushion. To increase sitting comfort, the cushion is actively ventilated, ventilation being performed by miniature fans, which draw in air from the rear side of the cushion and force it through the air-guiding layer of the cushion, the air flowing out again via the cushion cover. For this purpose, each miniature fan is inserted into a bush that passes right through the cushion pad, extends as far as the air-guiding layer and is open on the rear side of the cushion pad. The ventilation in the bolster-type side areas is performed by means of separate fans since the tacking channels separate the air flow that enters the face area from the bulging areas at the edges.
An object on which the invention is based is, in the case of a seat module of the type stated at the outset, to improve the quality of the module as regards sitting comfort and long-term stability without having to make concessions in terms of manufacturing costs.
According to certain preferred embodiments of the invention, this object is achieved by providing a seat module intended for a vehicle seat and designed as a seat cushion or backrest which can be actively ventilated, comprising: a cushion, which has a lower foam cushion layer impermeable to air, a central air-guiding layer made from a knitted spacing-fabric and an air-permeable upper foam cushion layer, a cushion cover, tacking for the upper foam cushion layer fixing and dividing the cushion cover into a face area and two side areas which extend in a longitudinal direction and adjoin the face area, and a cushion carrier that accommodates the cushion, wherein the air-guiding layer rests on the lower foam cushion layer in the face area and directly on the cushion carrier in the side areas.
The seat module according to the invention has the advantage that the knitted spacing fabric of the air-guiding layer, the structure of which makes it very hard, is a long way away from the surface of the cushion and is no longer imprinted on the surface, this contributing to comfortable seating in terms of both look and feel. The elimination of the lower foam cushion layer in the side areas of the cushion means that this advantage is achieved in these areas too without making the side areas undesirably voluminous. At the same time, this makes the side areas more resistant to the pressure exerted by someone getting into the vehicle. The air-guiding layer remains stable and does not exhibit any settling, even in the long term, especially in the highly stressed face area, with the result that optimized ventilation of the seat module is maintained even in the long term. By virtue of the remoteness of the knitted spacing fabric from the surface of the cushion, rustling noises emanating from the knitted fabric are also damped by the foam layer and are barely audible, if at all.
Since the air blown into the air-guiding layer by means of fans can, so to speak, penetrate between the tacking, the side areas are well ventilated and do not require separate fans. By virtue of the support of the air-guiding layer made from knitted spacing fabric on a solid-foam block, on the one hand, the said block resting on a deep-drawn central portion of the cushion carrier in the face area, and on the lateral portions of the cushion carrier, on the other hand, these lateral portions being raised in the side areas, the air-guiding layer is in an optimum position that allows maximum air propagation in the air-guiding layer. Fans inserted into the lower foam layer thus have an increased pumping volume, with the result that it is possible either to improve conditioning comfort through more fresh air in the seat module or to reduce the number of fans, which makes the conditioning comfort more economical.
Advantageous embodiments of the seat module according to the invention together with expedient developments and refinements of the invention are described below and in the patent claims.
According to certain preferred embodiments of the invention, a noise-damping film is inserted between the air-guiding layer and the cushion carrier in the side areas. Noises that would otherwise be produced by the hard knitted fabric of the air-guiding layer rubbing on the cushion carrier are thereby largely suppressed.
According to an advantageous feature of certain preferred embodiments of the invention, tacking channels are arranged in the upper cushion layer of air-permeable foam to accommodate the tacking that fixes the cushion cover and divides the cushion into a face area and two side areas. As a result, the knitted spacing fabric of the air-guiding layer is not compressed in the area of the tacking and air can flow unhindered out of the face area into the side areas within the air-guiding layer, thus ensuring adequate ventilation of the side areas without additional fans.
According to an advantageous feature of certain preferred embodiments of the invention, the cushion carrier has raised side portions of a plastic or metal cushion shell at least in the side areas of the cushion, these side portions extending away obliquely upwards and, in the side areas, directly supporting the air-guiding layer composed of knitted spacing fabric together with the upper cushion layer of air-permeable foam that covers it.
According to an advantageous feature of certain preferred embodiments of the invention, the cushion carrier has a spring core, at least in a, preferably central, part of the face area, this spring core preferably extending over the entire face area. As a result, the lower foam cushion layer is not supported rigidly but is supported resiliently, ensuring that, despite the high compressive stress in the face area, the foam does not form a solid block and become hard, something that would considerably impair sitting comfort.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.